The invention relates generally to a torsionally rigid, play-free, metal bellows-type flexible coupling for the torque-transmitting connection of two shafts, and more specifically to such a coupling capable of providing a rigid, play-free coupling between two shaft ends in which the shaft diameters may be of different sizes.
For connecting the metal bellows with the input and output shafts so that no torsional play can exist, the state of the art calls for two interfaces or joints, namely, one between the bellows and a hub and the other between that hub and the shaft. One drawback of the prior interfaces or joints is that they cannot be separated in a non-destructive mannerxe2x80x94such as welds provided in accordance with a variety of processes, joints using one, two or more adhesive bonds, or beads and flanges. For the second interface or joint between the hub and the shaft, conical connections, shrink washers, collets or radially clamping hubs have been used in the past.
In the prior bellows-type couplings, the necessity of providing two interfaces or joints causes the following drawbacks: high cost of fabrication, insufficient flexibility when adapting the coupling to the customers"" interface or connecting positions, and a high mass inertia due to the great number of components.
Where it is necessary to quickly provide a low-cost, torsionally rigid, elastic compensating coupling, an ideal coupling design would have to have the following advantages:
Combination of the two interfaces or joints to form one interface or joint; modular construction; adaptability to compensate existing shaft misalignment by simple replacement of the torque-transmitting metal bellows; torsionally play-free design; high torsional rigidity; low rigidity to displacement; low mass moment of inertia.
In order to obtain all the aforesaid advantages, the object underlying the invention is seen in the provision of a metal bellows-type compensating coupling which is inexpensive to manufacture, is modular to enhance its availability, is torsionally rigid and torsionally play-free and elastic, and in the installed condition does not substantially affect drive train dynamics.
This object is achieved by means of the characterizing features specified in the description below.
The principle underlying the invention is the functional combination of the frictional connections between the bellows and the hub and between the hub and the shaft to form a single joint, with the cylindrical or inwardly slightly tapered end of the bellows frictionally engaged with the input and output shaft directly or indirectly by means of an external clamping unit.
East German patent DD 147 742 discloses a metal bellows-type coupling in which the end of the metal bellows is flanged out in a generally axial direction (slightly tapered or cylindrical with a crimp) and is placed over a hub on the shaft. An external member not described in detail is used to clamp the end down on the hub and thus on the shaft.
DE-A-42 17 764 shows a metal bellows-type coupling in which a radially slotted clamping ringxe2x80x94compressible by the width of the slotxe2x80x94is used to clampingly engage the metal bellows with the shafts. The manner of connecting the metal bellows with the clamping ring is not described in detail; also, it engages the shaft directly.
According to the disclosure of U.S. Pat. No. 3,232,076, a metal bellows-type coupling is provided with a metal bellows axially cylindrically flanged out at its ends, said ends being introduced in recesses machined in internally tapered threaded sleeves. These sleeves receive external nuts which are oppositely tapered internally. The tapered bores receive an axially slitted double cone surrounding the shaft. Tightening the nut causes the double cone to be compressed radially and to be clamped down on the shaft.
The metal bellows coupling of U.S. Pat. No. 4,645,473 comprises a metal bellows with cylindrically flanged ends each seated on a ring. Adjoining the rings are axially hollow, longitudinally slitted sleeves having tapered outer threads thereon, said rings being placed on the shafts; tightening the threaded sleeves will radially compress them to clamp the metal bellows onto the shaft.
The journal xe2x80x9cAntriebstechnikxe2x80x9d 1997, issue no. 10, page 88, discloses a metal bellows-type coupling comprising a unit assembled of the metal bellows and a hub adhesively bonded thereto, said unit being placed on a hub connected with the shaft.